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DIAGNOSIS: The "off the shelf" map has a boost peak of ~13psi. I was peaking at ~15psi in 4th WOT at about 5000rpm. After contacting Cobb about my issue they explained that the map is designed for vehicles with stock or Cobb cat-back exhaust only. The Perrin exhaust is known to be more "free flowing" and can create this very issue. After contacting Perrin they explained that their stage 1 map is designed with peak boost around ~15psi to avoid this exact issue. After contacting Shawn at Rallitek he explained the best way to fix the problem is to make a "pro-tune" map for my car which will release its full potential and avoid any further issues.

RESULT: Shawn and I proceeded to "pro-tune" my car and I am VERY satisfied with the results. After running the Dynameter on the AP in 4th gear from 2000rpm to 5200rpm the estimated wheel power was 254hp and 317lbs. Not bad for stage 1 with cat-back only!

I know this seems like alot of work for stage1 when I could have avoided some of the headache and just gone stage2 with a downpipe... but not everyone is within a few miles of Perrin, Cobb and Rallitek! Others installing Stage1 with just a cat-back may run into similar problems and hopefully this write-up can help!

It is very odd that your car was boost creeping with just a catback. Normally, the TD04 will not boost creep, even with a completely catless system. Did you take any datalogs of what was going on? How were you determining that you were boost creeping?

I logged my boost level with the accessport multiple times. The map notes for the Cobb map state a boost peak of ~13psi... I was peaking at 15.1 to 15.4psi

The CEL I was given was p0244... wastegate solenoid A... leads me to believe the "free flowing" of my exhaust is not causing the problem, but the wastegate itself is not funtioning properly to obtain required boost level (which to my knowledge is controlled and set by its parameters within the map)

Well I am happy to report that what you were seeing was NOT boost creep. Boost creep happens usually around redline or the top end of the RPM band where the ECU has openeing the wastegate fully but the turbo still builds boost, this is mechanical in nature and tends to not be fixable by tuning.

Your car was not boost creeping. It hit a bit more boost than what the target in the midrange for a few tenths of a second and the ecu corrected it, as it should. I would say that this map would have been fine to run. You can see in the turbodynamics column that there is a "-9" value or so. This is the ECU attempting to run less boost and you can see the next logged CEL that boost has dropped to 12psi, which is about right for the target for that map.

I realize that Sean at Rallitek was able to help you out with tuning. If you are ever in any need of a full dyno tune, come see us at COBB Tuning Surgeline. Thank you for sending in the log.

I have an 08 Forester XT 4EAT flashed with Cobbs Accessport 93 octane stage 1 AT map and keep throwing the P0244 CEL during wide open throttle from a stop. Only mods are the AP and a TXS axle back. Any idea what my issue might be? This started about two weeks ago and has happened twice.

The famous ''Mikey'' Dude all i hear is how you tune everyones Subaru here lol I'm not sure if im ready for a protune yet due to the fact that i just noticed that my clutch is slipping so i need a new one. Also because i still want to do a couple more performance parts but would like to meet you. How much would you charge me for a protune or if you could just help me with that it would be perfect and when im ready for the protune ill wait for your next visit.

It is very odd that your car was boost creeping with just a catback. Normally, the TD04 will not boost creep, even with a completely catless system. Did you take any datalogs of what was going on? How were you determining that you were boost creeping?

Travis
COBB Tuning

Agreed I have a TD04 with a full 3" catless exhaust and I'm lucky if I can pull 12-12.5psi WOT at 5K and it's tuned for 15 at this rpm. This tiny turbo is just hopelessly out of steam at this point.

Agreed I have a TD04 with a full 3" catless exhaust and I'm lucky if I can pull 12-12.5psi WOT at 5K and it's tuned for 15 at this rpm. This tiny turbo is just hopelessly out of steam at this point.

It is strange. I was hitting 17-18 peak (Stg 1 93 oct OTS map)and was concerned to say the least. After looking and charting some logs I found that, like the Cobb guy said, it would just peak and settle back down at the next data cell from the peak # after the ECU made correction.

Cobb: I assume that this is an untunable delay in the mechanical action of the WG trying to catch the ECU adjustments? Is it good for the longevity of the turbo getting outside its efficiency bands, even if for a brief moment? Since at those pressures that turbine is going much faster than safely designed for. Also, could we be seeing detonation at that point in time? NEED MOAR LOGS. I love this stuff. Should have went into Mechanical rather than Civil....I do know a lot about pumps, just big water distribution ones. Turbos are the same thing, just pumping air instead!

It is strange. I was hitting 17-18 peak (Stg 1 93 oct OTS map)and was concerned to say the least. After looking and charting some logs I found that, like the Cobb guy said, it would just peak and settle back down at the next data cell from the peak # after the ECU made correction.

Cobb: I assume that this is an untunable delay in the mechanical action of the WG trying to catch the ECU adjustments? Is it good for the longevity of the turbo getting outside its efficiency bands, even if for a brief moment? Since at those pressures that turbine is going much faster than safely designed for. Also, could we be seeing detonation at that point in time? NEED MOAR LOGS. I love this stuff. Should have went into Mechanical rather than Civil....I do know a lot about pumps, just big water distribution ones. Turbos are the same thing, just pumping air instead!

Best thing to do is to get a data log as outlined in the video below (if you can do so safely). Check out the maps notes found in the maps section at cobbtuning.com for your car. It will indicate the peak boost you should see and what it should taper to near redline. You should not exceed peak boost by more than 1 psi in any gear. If you are, then you would want to download the low wastegate (LWG) map (also in the maps section at cobbtuning.com) and reflash to the car. This should bring boost levels down. Get additional logs to verify.